Atlantic halibut aquaculture faces unique welfare challenges including high rates of ambicoloration in juveniles, which reflects developmental stress and has welfare implications throughout the production cycle.
Ambicoloration in farmed halibut is an important welfare indicator because it reflects suboptimal conditions during a critical developmental period. The metamorphic transition from pelagic to benthic life is physiologically demanding, and stress during this phase produces lasting developmental consequences including abnormal pigmentation. Beyond its role as a welfare indicator, ambicoloration may compromise individual fish welfare by affecting their behavioral repertoire — ambicolored fish often show atypical behavior compared to normally pigmented conspecifics. The overlap between welfare optimization and commercial incentive in reducing ambicoloration rates makes this an area where industry and welfare science align well. Research into light quality, intensity, and photoperiod during metamorphosis is producing actionable improvements in both welfare and production outcomes.